Is there any benefit to using Mipmaps in very large scenes?

[Anonymous]

Hi Everyone,

I was wondering if there was any benefit to creating Mipmaps for textures that will just be used in a still image?

Has anyone tried loading them in a VRay HDRI map and using them in Corona?

I often work in extremely large and heavy scenes with multiple cameras all over a scene, if my understanding is correct mipmap textures could be useful so less RAM and processing power is used at render time computing large resolution textures that may be needed in some camera views but are very small in others.

The file size for the mipmaps is larger than a normal map, does this slow down part of the rendering process that might negate any benefit from a mipmap?

Also what are the differences between .TX, tiled .EXR and DDS?

Any help is greatly appreciated, most information out there is for game engines.

[jon.bell]

Hello,

Thanks for your question.

I can't address the benefits of using mipmaps for the Corona renderer, but our Arnold renderer works quite efficiently with textures converted to .tx format (which are effectively tiled .tif files, if I'm not mistaken. The free IrfanView image viewer plugin will actually load and display .tx files, but will first give a warning message saying that the file appears to be a .tif with an "incorrect" extension.) The ability to load only portions of a required, visible texture at render time allows Arnold to crunch through enormously complex 3D scenes. Maya has a built-in .tx texture converter, and 3ds Max should get this capability in the not-too-distant future. (At present, you can use 3rd-party scripts with the maketx.exe utility to batch convert your textures.)

I'm not sure of the differences between .tx, tiled .exr and .dds, but I'll check with some of our Solid Angle developers to see if they can chime in here with a better technical explanation. And if any of our other customers wants to chime in here, please do so!

Best regards,

[Stephen.Blair]

If you were using Arnold, there's an advantage to using tx files: better texture cache usage, which means better performance and memory usage. 

There's no good reason not to use tx files. Again, I'm talking about Arnold.

I can't speak for other renderers.

A tx file is just a renamed tif or exr (depending on how it was converted). But it has some additional info, like a hash of the image, that allows OIIO to do things like detect duplicates and constant colored textures.